The latest clinical hold was placed after a patient experienced serious adverse events that included neurotoxicity and cytomegalovirus infection, as well as severe respiratory distress.
Shares of Unum Therapeutics fell as much as 23 percent in premarket trading after the company announced late Tuesday the U.S. Food and Drug Administration (FDA) placed a clinical hold on its Phase I non-Hodgkin lymphoma trial due to safety concerns. This is the second clinical hold on this drug.
The clinical hold was placed on Cambridge, Mass.-based Unum’s early-stage ATTCK-20-2 trial investigational the company’s asset ACTR087 in combination with rituximab (Genentech’s Rituxan) following lymphodepleting chemotherapy with fludarabine and cyclophosphamide in patients with relapsed/refractory CD20+ B cell non-Hodgkin lymphoma. Unum said the hold was placed on the trial after the company submitted a safety report to the FDA regarding one patient in the safety expansion cohort of the trial who experienced serious adverse events that included neurotoxicity and cytomegalovirus infection, as well as severe respiratory distress.
This is not the first time that Unum has had a safety issue with ACTR087. Last year, ahead of the company’s intention to file an initial public offering, the company reported that a patient died following an ACTR087-related severe cytokine release syndrome. Also, two other patients who received the highest dose of ACTR087 died from serious adverse events. The deaths forced the FDA to place a clinical hold on the trial. That hold was later released.
In May, Unum announced it completed enrollment in the ATTCK-20-2 trial. Despite the hold on the trial, the FDA said patients who have received ACTR087 and have ongoing clinical responses may continue to receive rituximab infusions, with continued monitoring for adverse events. Unum said it will continue to work closely with the FDA to further review these events. The company plans to report data from the ATTCK-20-2 trial at the end of 2019.
At one point ACTR087 was Unum’s lead asset, however last fall, the company deprioritized ACTR087 in favor of a new ACTR construct, ACTR707, the same disease setting. Additionally, Unum said earlier this year that it intends to test ACTR707 in combination with Genentech’s Herceptin (trastuzumab) in HER2+ solid tumors.
Unum’s ACTR technology is part of the ever-growing immuno-oncology field. Its ACTR product candidates take T cells from patients and then genetically modify them to express the ACTR protein. ACTR is a chimeric protein which combines parts of proteins found on both T cells and natural killer cells to create a doubly-powerful attack on cancer cells. The modified cells are then re-administered to the patients with a tumor-specific antibody.
